1. Field of the Invention
The present invention relates to digital camera modules and, particularly, to a digital camera module with an automatic focusing structure and a method for assembling the same.
2. Description of Related Art
Digital camera modules are widely used in portable electronic devices such as mobile phones, and personal digital assistants (PDAs). In order to attain a better image quality, many digital cameras have an automatic focusing structure. The focusing structure can be used for adjusting distance between the lens module and the image pickup device to make a clearer image when photographing objects at different distances from the camera.
Referring to FIGS. 7-8, a typical digital camera module 100 with an automatic focusing structure includes a lens module 12, a focusing structure 14, and a chip package 16. The lens module 12 includes a barrel 121 and a holder 122. The holder 122 has a through hole 1222 defined therein, so that light can be transmitted therethrough. Several lens elements 123 are fixed in the barrel 121, and the barrel 121 is slidably received in the through hole 1222. A plurality of channels 124 is defined in the holder 122. Each channel 124 has a first end opening 1242 and an opposite second end opening 1244. The first end opening 1242 communicates with the through hole 1222. The second end opening 1244 communicates with the bottom outside of the lens module 12. Each channel 124 receives a wire 125, and the wire 125 extends out from the two end openings 1242, 1244 of a corresponding channel 124. The focusing structure 14 is fixed in the holder 122, so as to seal the first end opening 1242 of the channel 124 and electrically connect with the wires 125. The focusing structure 14 connects with the barrel 121 so as to drive the barrel 121 to move up and down. The chip package 16 includes a chip module 162 and a base 164. The chip module 162 is mounted on a central area of the base 164. A plurality of pads 166 is mounted on the periphery of the base 164, electrically connecting with the chip module 162.
In assembly of the lens module 12 to the base 164, some conductive adhesive 18 is dropped on the pads 166 of the base 164. The second end openings 1244 of the channels 124 correspond to the pads 166, respectively. The lens module 12 is placed on the base 164 and bonds with the base 164 when the conductive adhesive 18 becomes solidified. At the same time, the wire 125 electrically connects with a corresponding pad 166 by means of the conductive adhesive 18. Accordingly, the chip module 162 may control the focusing structure 14 to adjust the distance between the chip module 162 and the lens elements 123 to attain a clearer image when photographing objects at different distances from the camera module 100.
Generally, the channels 124 are thin and the second end openings 1244 are narrow, so that it is difficult for the liquid conductive adhesive 18 to completely flow into the channels 124 via a corresponding second end opening 1244. Therefore, the liquid conductive adhesive 18 might overflow from the channels 124 and touch the outside during assembly, and, as such, the appearance of the digital camera module 100 might be affected. In addition, the signals from the chip module 162 to the focusing structure 14 might be distorted from the outside via the overflowed conductive adhesive 18. Accordingly, the ability to adequately adjust the displacement of the chip module 162 relative to the focusing structure 14 might be adversely affected. Furthermore, some liquid conductive adhesive 18 is pressed into the channels 124 during assembly. When the conductive adhesive 18 is solidified, the channels 124 are sealed with some air therein. The air in the channels 124 might expand when hot and contract when cold so as to create an unplanned/unaccounted source of variability within the combination of the elements of the digital camera module 100.
Therefore, a digital camera module and a method of assembling the same are desired in order to overcome the above-described problems.